The invention relates to a device for controlling outflow from a tank, especially a rain-retaining chamber or the like with an outlet opening for the liquid, and is particular to a device wherein the outlet opening is assigned a shutter that can be moved in a straight line to control the outflow of the liquid from the container as a function of the liquid level in the tank.
In rain retention chambers and other storage chambers, the outflowing water quantity is generally controlled by changing the cross section area of the outlet opening. However, the shuttering cannot be controlled directly proportionally to the water level; rather it must be controlled in the direction of a slower shuttering with increasing backwater height.
Numerous variations of such devices to control the constant outflow from a tank are known from the state of the art. They usually use a float, i.e., a component whose position can be changed depending on the liquid level in the tank. By way of a rod or the like, the float actuates the shutter, which has the function of a gate or throttle element.
A device such as this is known from DE 32 40 902 A1. In it, the shutter is guided in a vertical direction in front of and over the outlet opening. The float is mounted so that it can swivel around a stationary horizontal axis by way of a float rod. A control disk with a curve located on its circumference is connected so that it rotates mutually with the float rod, in the area of its swivel bearing. An angle of a guide rod that holds the shutter rides on the curve. The stroke of the guide rod is thus regulated using the control disk driven by the float. In the case where high water levels have to be managed, providing a control with several independent floats is suggested, which interact with control disks arranged over each other. In this case, the guide rod is elongated accordingly and has a curve rider at the height of the control curve of each control disk. A device such as this has a very complicated construction. Besides that, it does not allow an exact control of the constant outflow with substantial backwater heights. In addition, such devices cannot be built in compact form because of the float construction.
EP 0 707 254 A2 describes a device of the type discussed above, in which the shutter is controlled by way of a curve by a component whose position can change depending on liquid pressure. In this case, a boot is provided that is mounted in the area of one of its ends and the other end of which holds a plate-shaped control element that is provided with a curve, whereby this curve is formed by a flank of a control slot of the control element. The shutter is mounted so that it is guided vertically, whereby a horizontal pin connected with the shutter engages in the control slot. A horizontal driving movement of the control element during expansion and/or contraction of the boot leads to a vertical movement of the shutter in opposite directions. What is especially disadvantageous in such devices is that the horizontal displacement of the control element that is linked with the displacement of the boot does not allow precise regulation of a constant flow. This is especially true because the curve has a control length that is too short.